1. Field of the Invention
The present invention generally relates to appliance timers, and more particularly, to an appliance having a timer with a sensor for facilitating, among other things, additional switching functions for the appliance.
2. Background of the Invention
Appliance timers are commonly used in many household appliances, such as clothes washers, clothes dryers, dishwashers, etc. The appliance timer controls operation of the appliance by actuating and deactuating switch assemblies which start and stop various functions within the appliance such as a rinse function in the case of a clothes washer. The switch assemblies within the appliance timer are actuated and deactuated as a result of interaction between a number of cam followers which are respectively associated with the switch assemblies.
The switch assemblies are generally grouped into a number of switch blocks associated with the appliance timer. For example, one common switch block configuration includes eight switch assemblies. Moreover, each of the switch assemblies typically includes an upper circuit blade and a lower circuit blade, with an intermediate circuit blade positioned therebetween. The circuit blades are moved into and out of contact with one another in order to make and break, respectively, a number of circuits. In particular, if the circuit blade has a cam follower molded or otherwise secured thereto, the circuit blade may be moved into and out of contact with other circuit blades via cooperation with one of the cam surfaces defined in the camstack. Alternatively, if the circuit blade is configured without a cam follower, the circuit blade will remain stationary until another circuit blade associated with the switch assembly is moved into or out of contact therewith. One common switch assembly arrangement includes an upper and a lower switch blade, each of which is configured without a cam follower. Actuation of the switch assembly occurs as an intermediate circuit blade, which has a cam follower secured thereto, is selectively lifted into contact with the upper circuit blade or dropped into contact with the lower circuit blade.
One way to categorize appliance timers is by the number of switch blocks included in the timer. For example, appliance timers may be categorized as either “single block” timers or “double block” timers. As their respective names suggest, a single block timer includes a single switch block (e.g., a single group of eight switch assemblies in operative contact with the camstack), whereas a double block timer includes two switch blocks (e.g., two groups of switch assemblies each having eight switch assemblies in operative contact with the camstack).
Single block timers advantageously have fewer components relative to double block timers thereby reducing costs associated with the appliance timer. Hence, a number of single block timers have heretofore been designed for use in many household appliances. Such single block timers are used in conjunction with appliances which do not require the additional switching capacity associated with double block timers. For example, it is known that approximately 85% of the clothes washer and dishwasher models available in the appliance market may be operated with a single block timer. Therefore, the use of single block timers in such appliances provides the switching capacity necessary to operate the appliance without additional costs associated with double block timers.
However, the remaining models, often referred to as “high-end” models, require more complex timing functions which may be achieved with a double block timer. This is true since high-end models generally have additional features associated therewith thereby increasing the number of switches required for operation of the appliance. As alluded to above, while use of such double block timers increases the switching capacity associated with the timer, costs associated with the timer are also increased thereby disadvantageously increasing costs associated with the appliance. What is needed therefore is an appliance timer which has greater switching capacity, and hence greater functionality, relative to single block timers which have heretofore been designed, but has fewer components relative to double block timers which have heretofore been designed.
One attempt at such an appliance timer is disclosed in U.S. Pat. No. 6,064,011 issued to Amonett, the disclosure which is totally hereby incorporated by reference in its entirety. Referring to FIG. 1, an appliance timer of the type disclosed in the Amonett '011 patent is shown. In particular, the appliance timer of FIG. 1 includes a voltage source 13, first machine components 15, second machine components 17, a switch block 22, a camstack 24, and an auxiliary assembly 26. The switch block 22 includes switch wafers 28, 32 and 36. The auxiliary assembly 26 is provided to increase appliance switching capacity and functionality, and includes an auxiliary member 62 bearing a circuit pattern 72, and an auxiliary wafer 76 having conductive arms 74.
As indicated in FIG. 1, the voltage source 13 provides a voltage signal to the switch wafers 28, 32 and 36 of the switch block 22, and the auxiliary wafer 76 of the auxiliary assembly 26. As the camstack 24 rotates, the switch wafers 28, 32 and 36 of the switch block 22 perform switching operations that control the first machine components 15, such as motors or heaters. Accordingly, the first machine components 15 may include heavy-duty circuits (e.g., circuits which carry a current of 13 to 15 amps) of an appliance.
Rotation of the camstack 24 also causes rotation of the auxiliary member 62 of the auxiliary assembly 26. As the auxiliary member 62 rotates, the conductive arms 74 of the auxiliary wafer 76 contact the circuit pattern 72 on the auxiliary member 62, and thereby generate voltage signals which control switching operations of the second machine components 17. However, in order to facilitate manual setting of the appliance timer by a user, the contact force between the conductive arms 74 and the circuit pattern 72 is relatively small so that, for example, a dial or other input means connected to the auxiliary member 62 can be easily rotated by a user. Because of this relatively small contact force, the electrical current generated by the auxiliary assembly 26 is also relatively small in magnitude. Accordingly, the second machine components 17 controlled by the auxiliary assembly 26 must be light-duty circuits (e.g., circuits which carry a current of less than 2 amps) of an appliance, namely circuits that operate features such as indicator lights, electrically-actuated water valves, etc. In other words, the auxiliary assembly 26 of FIG. 1 is not suitable to provide switching operations for heavy-duty circuits of an appliance.
Accordingly, there is a need for an appliance timer which, among other things, provides: (1) greater functionality relative to single block timers; (2) fewer components relative to double block timers; and (3) is suitable to accommodate switching for both light and heavy duty circuits. The present invention addresses these and other issues.